1. Field of the Invention
This invention relates to a circuit arrangement for an electric appliance, having a control device and a power supply unit connected with an electric current supply connector for providing functional units, which are to be controlled, of the electric appliance with current, wherein there is a switch on the electric current supply connector for cutting off the power supply unit from the electric current supply connector on a primary side.
2. Discussion of Related Art
It is known to equip electric appliances used, for example in the household, with electronic controls. Electronic touch controls are employed in particular for stove top cooking units, stoves, dishwashers, washing machines and similar household appliances. One disadvantage is that the touch controls must be maintained ready, to be able to react to inputs. In the process, known appliances use a so-called quiescent current that is determined by the power use of the implemented electronic circuits and the losses of the power transformer. Typically, the power consumption is about 1 W. Although such a power consumption is relatively low, overall it can result in a considerable quiescent current consumption in connection with a large number of conventional devices.
It is also known from the prior art to produce electronic controls without quiescent current consumption. Here a central mechanical switch can be provided. However, it is disadvantageous for the operating concept of touchless switches to be disrupted. For changing the state between ON and OFF, the mechanical switch requires a path for the toggle switch. Thus the operating surface must have an opening that increases production costs for such an operating surface, cleaning is more difficult, and it is necessary to accept limitations in the design.
A stove top cooking surface is known from German Patent Reference DE 199 23 148 A1, wherein the energy supply can be switched on via a Reed contact. However, the use of a Reed contact is disadvantageous because a magnet is required for activation, which is easily lost under certain circumstances.
German Patent Reference DE 199 44 235 A1 discloses shutting off the energy supply of a stove top cooking surface as taught by German Patent Reference DE 199 23 148 A1 by a Reed contact. Thus the magnet is only required to place the electric appliance into a rest state without using quiescent current. If the magnet is lost, the electric appliance continues to use energy in the rest state.
German Patent Reference DE 199 32 453 C2 discloses making a household appliance available in the rest state without quiescent current use. Here, the power supply unit of the household appliance is switched on by a thyristor, which is switched on by an optical coupler via a data network outside of the appliance. It is thus possible to locally switch off the household appliance so that no quiescent current is used, and to switch it back on again via a central control device. Thus no energy is used during the night or during vacation time. However, the consumption in the still remaining stand-by time is disadvantageous, because the energy consumption of the central control device is used during the entire day.